The present invention relates generally to spacecraft communication systems, and more particularly, to a dual autotrack control system and method for autotracking multiple antennas to compensate for disturbances to a spacecraft.
The assignee of the present invention manufactures and deploys communication satellites or spacecraft that use multiple communication antennas. RF autotracking controllers have heretofore been used to steer individual antennas to compensate for disturbances to the spacecraft. Furthermore, only single control algorithms were used to steer an antenna. Sensing and actuation occurred at a high rate to compensate for the fastest disturbance, such as spacecraft motion, which typically affect all the antennas on the spacecraft in the same manner.
More specifically, in prior systems that provide for RF autotrack control of multiple antennas, each antenna utilized a single control algorithm and a dedicated set of sensors to compensate for the most rapid disturbance. The most rapid disturbances are typically those common to all of the antennas on the spacecraft. Such rapid disturbances include spacecraft motion disturbances. The RF sensor was used to multiplex between the multiple antennas to save on hardware and software costs, but unfortunately at a cost of degrading the pointing performance of the antenna to the point where the common mode disturbances could not be corrected.
It would therefore be desirable to have an autotrack control system for use with multiple antennas that compensates for fast and slow disturbances experienced by a spacecraft. Accordingly, it is an objective of the present invention to provide for a dual autotrack control system and method for autotracking multiple antennas to compensate for disturbances to a spacecraft.